Bearing for rotary spindles



i9 1, 133415 w. G. BALDENHOFER 2,384,589

BEARING FOR ROTARY SPINDLES Filed Aug. 16, 1941 2 Sheets-Sheet 1 WuOFER,

.J WILLIAM G. BALDEMH 1 a N .e m R m l) 11/ Ill/I111} 2 Sheets-Sheet 2ruvamoa Bmmom ATTORNEYS! &

m E I) 1 K i I I I I I p o 6) B Wmmm w. G. BALDENHOFE R BEARING FORROTARY SPINDLES Filed Aug 16, I941 Sept. 11, 1945.

The general object of the invention Patented Sept. '11, 1945 PATENTOFFICE BEARING FOB ROTARY SPINDLES William G. Baldenhofer, Springfield,Ohio, as-

signor to The Thompson Grinder Company, Springfield, Ohio, a corporationof Ohio Application August 16, 1941, Serial No. 407,184

The present invention relates to bearings for rotary spindles such asused particularly in various kinds of machine tools, as for example. ina grinding machine.

In the bearingart it is customary to provide a pair of radial bearingson opposite sides of a thrust bearing, each of the bearings comprising aplurality of pivotally mounted shoes. The problem of accuratelyadjusting the shoes at each of the bearings is often diflicult as thevarious elements are contained within a completely enclosed housing andsubjected to oil under pressure. The shoes often need replacementparticularly in the case of high speed rotary spindles which carry agrinding wheel at one end and a motor at the other end, and thereforesubject to considerable torsional and gyroscopic strain. Various wayshave been devised for making the necessary adjustments for replacementsof the various beering parts but in all cases the structure iscomplicated and the work required in making the necessary changes isconsiderable.

The primary object of the present invention is to provide an improvedbearing structure for high speed rotary shafts, spindles and the likewhich are employed in the modern grinding machine,

boring mill and similar machines.

A more specific object is to provide a grinder spindle with associatedradial and thrust bear- 'ings which may be readily assembled,disassembled and adjusted to eflect the proper relationship between thebearing surfaces thereof and against improper axial displacement.

A still further object is a provision of means for supplying lubricantto both oi? the radial and thrust bearings. is to provide a high speedrotary spindle with improved radial and thrust bearings so arranged asto be readily taken apart, inspected and adjusted together with improvedmethods of lubrication, all of which are relatively. inexpensive andoperate with the highest efiiciency.

Other objects and features will be apparent as the specification isperused in connection with the accompanying drawings in which:

Figure 1 is a longitudinal section through the improved hearing butshowing the shaft and a few other structural details in elevation;

Figure 2 is a sectional view taken along lines 2-2 in Figure 1 andlooking in the direction of the arrows; and

Figure 3 is a. similar view taken along line 3-3.

Figure 4 is a longitudinal sectional view of the improved bearing butwith the lower half dropped improved.

away from the upper half to show the method of assembly and disassembly.

Figure 5 is a perspective view of the liner or split sleeve whichanchors the radial shoes in place.

Referring more particularly to Figure 1, nuneral I generally designatesa portion of a grinding machine frame in the region" of the rotaryspindle 2 which carries a grinding wheel ,3 or

other abrading or cutting tool. The spindle isprovided at one end with atapered portion 6 terminating in a threaded extension 5. A clampingplate 5 is mounted over the tapered portion and is held in position byanut 1, which is secured to the spindle at the threaded end 5. Theclamping plate 6 is provided at its under side with an integral radiallyextending portion 8, which serves as a backing member for the grindingwheel 8, the latter being clamped to the backing member by means of aplate 9 which is threaded on a shoulder formed in the element 6. A guardH! of any suitable and well-known type may be positioned on oppositesides of the grinding wheel, this guard preferably extending over theentire wheel periphery except at the lower end where the wheel comes incontact with the work.

The frame i is usually a casting formed in two halves joined together bybolts H at each end which passes through bosses Ma. The two frame halvesare aligned by shoulders lib cut into the abutting surfaces. Theassembled frame is provided with bores lie at the respective ends, andtightly fitted within these bores there is a shoe spacing ring ii. Thebores llc are formed in a shoulder portion indicated at l3, the ring l2being secured in the axial direction to the shoulder by means of anundercut plate It which may be secured to the frame I. The plate H hasan internal diameter such as to leave an annular space about the shaft,and an oil seal ring I5,is

mounted in this annular space. The shait is provided-with an oilretaining or oil flicking ring it at a position adjacent the oil seall5.

Each ring i2 is provided at its inner surface with a flange I! whichextends inwardly almost as far as the shaft, this flange being providedwith an annular groove 18 to which access is made by means of threeopenings spaced about the flange as indicated in Figure 2. Theseopenings receive pipes or conduits [8 closed at one end and containing alarge number of apertures 20. The annular groove IB is completelyenclosed by a grooved plate 2i which is screwed as indicated at 22 tothe end of the ring i2. The plate 2| is provided with an opening beingconnected each block or shoe and the bore.

provided with a hardened methlinsert 2} which projects slightly beyondthe outeri'urface of the shoe and is given a spherical configuration ofathrough a pipe conduit system '24 to a high pressure oil pump (notshown). 011 under pressure can therefore be supplied to each groove II,this oil being forced out through the openings in the form of amulti-spray stream on to the shaft for purposes which will be describedpresently.

The radial bearings for the shafts are mounted at each end of the framehousing and the rings it contained therein are positioned at each radialbearing. The ring is split horizontally as indicated at 28 similar tothe housing and the ring portions are held in position by the clampingeffects of the bolted frame halves. Each ring is provided preferably inthree positions about its periphery with rectangular openings 2's(Figure 5) for loosely receiving the extensions 28b of the shoes. Theseshoes are illustrated at 21 in Figure 2 and are constituted of elongatedrectangularly shaped blocks of metal provided at their inner surfaceswith a lining of bearing material it such as babbitt. The shoes 21 arepermitted to and longitudinal directions. and for this purpose are givena cylindrically shaped surface with a predetermined clearance betweenthe ends of Each shoe is somewhat smaller diameter than the cylindricalcurvature of. the shoe. The insert 2! contacts at its outermost surfacewith an insert 3| of hardened metal secured to the housing 2! in anysuitable and wellknown manner. The insert It is assesao accommodate ofthe shaft or the bearing and in addition the bearing surfaces areadequately lubricated by the forced prenure system.

In accordance with another feature of my invention there is provided animproved thrust rock along the interior surface of the bore ii in theperipheral bearing for preventing translational or axial displacement ofthe shaft within the bearing. For this purpose, the shaft 2 is providedwith a thrust collar is which'dips into the oil reservoir at its 'lowerend, and at its upper end is provided withthrust bearing shoes of thesame general type as spherical surface whereit contacts with the insert.7

so. The distance between. the shoes to and therefore the pressureexerted at the thrust collarmay beeontrolledbytheaetscrewslhand when thelatter have been properly adlluted. they are locked into position byascrew 42. Asia the case of the radially positioned shoes, the shoes 8|areadaptedtotiltorrockatthepointto'point preferably given a fiatconfiguration where it contacts with the insert 2!. 1

It will be noted that the lower shoe is of greater length as measuredaround the periphery of the shaft thaneither of the other two. shoes inorder to accommodate the greater pressuresexercised at this point due tothe weight of the shaft and the grinding wheel. This lower shoe isprovided with the hardened metal inserts similarly to the other shoesbut the insert which is fitted at the housing forms part of a screw 33which may be rotated from the exterior of the housing in'order to movethe lower shoe either toward or away from the shaft as may be desired.After the lower shoe has been properly adjusted it is locked in positionby means of a screw 34 which enters the housing from the side and isadapted to bear against the screw 38.

contact made between each insert II and the set screw so that the endbearing can accommodate itself to an irregularity in the end movement ofthe shaft.

"Adequate lubrication of the contact surfaces between the collar 3'andthe bearing metal I is provided by the oil which is picked up fromthe reservoir by the collar II and carried around to the bearing. Forcedlubricationis not necessary at the thrust bearing because there are nohilh pressures exerted by the grinding wheel in the .extreme casesoccasioned-when the grinding a It will also be seen from Figure 2 thatthe lubrieating pipesli are positioned directly in front of the leadingedge of each shoe assuming that the shaft is rotated clockwise, theposition of the openings It in the pipe ll being such as to directlubricating fluid under pressure against the forward edge of each shoe.Due to the presence of the spherically shaped inserts" and assumingproper adjustment has been made at thegscrew It, the shoes may tilt orrock appropriately to establish and maintain proper-bearing films of oilbetween their bearing surfaces II and the peripheral surface of theshaft spindle 2. The oil. after leaving the shoes will pass along theshaft toward the center and will collect in a reset voir indicated at IIformed at the middle of the housing. The excess oil may be withdrawnfrom the reservoir through a pipe conduit indicated at II. It isapparent that the construction as described-provides for aself-adjusting frictionless radial hearing at each end of the spindle 2,the

bearing shoes being adapted to tilt or 00k to ing with an annular grooveit to whichlubrication is supplied under pressure represents not axialdirection. so that the thrust bearing is called upon to accommodate onlythe end movementsoftheshaftbrought aboutbywearandin wheel 8 is riding aridge which gives it a component of movement in the horiaontaldinetion.' on the other hand the radial bearingis required toaccommodate large pressures of a variable "character in the radialdirection and for that reason forced lubrication is highly desirable.

. The use ul the apertured Pipes it communicatonly an inexpensive buthighly efficacious mannor of providing the necessary lubricationat the.radisl bearings. The arrangement is such that the pipes can be readilymounted in their open,

'ings in the ring I! at which'time they mausomatically brought intocommunication with the annular groove l8 and thelstter is-clossd in arelatively similar manner by merely mm the plate ii. The presence of theoil sealing ring. II and theoil retaining ring It completelypreven-ts'any migration or creeping of the oil toward the ends of'theshaft,-even when the pres- 'sureoftheoilisashighasfivepoundsper squareinchso thatthebearingasawhole'il maintained clean'and free from oildrip.

The manner in which the combined and radialthrustbeariugmaybetakenapartfq in- The frame member I is provided withspection, repair or adjustment is illustrated in Figure 4. The bolts Iiare withdrawn permitting the lower half of the housing 25 to be removedfrom the upper half at the split surfaces and the lower half of the ringl2 together with the lower radial shoe may be also simultaneouslyremoved at this time. It will be noted that the left hand end (Figure 1)of the housing 25 just clears the guard Ill of the grinding wheel sothat it is unnecessary to remove either the guard or the grinding wheelin order to disassemble the bearing. After the lower housing 25 and thelower part of the ring l2 have been removed in the manner stated, theupper half of the ring l2 can then be. rotated about the bore ll untilit is free of the upper half of the housing. Consequently, all of thethree shoes in each of the radial bearings can be effectively removedfrom the bearing by simply loosening the bolts H and removing the entirelower half of the bearing. After the shoes have been inspected orrepaired they may be reassembled in the reverse o'rder than that statedabove and all of these operations take place without dropping the shaft2 or the thrust bearing entirely from position. When the lower half ofthe housing 25 is removed the shaft 2 is held in position at the motorend on account of the coupling with the motor shaft (not shown). At theopposite. or grinding wheel end the shaft is held in position by reasonof the interior shoulder of the element 6 resting on the internal lowersurface of the guard Hi. It will be understood that the guard is securedin any.

suitable manner to the frame of the machine. The shaft and the grindingwheel 3 may bethen bodily removed from the upper housing after all ofthe end thrust and radial thrust shoes have been removed and thecoupling between the shaft 2 and the motor has been disconnected. Theguard it may be disconnected from the frame after the bearing housinghas been disassembled. When theradial shoes have been disassembled asexplained hereinbefore, ready access can be had to the set screws llwhich adjust the pressure applied by the thrust bearing shoes againstthe collar 88.

It has been pointed out that the openings 26a in the split ring i2 areof rectangular configuration and have a closed perimeter. Therectangular shape of the opening prevents any tendency of the shoes torotate in the horizontal direction and the fact that the openings are ofclosed perimeter provides support to each shoe in all horizontaldirections. Thus the ring 12 serves not only to space the shoes in theirproper positions about the shaft 2 but in addition prevents any improve:movement or each shoe which might introduce friction at the bearing.

It will be understood that I desire to comprehend within my inventionsuch modifications as come within the scope of the claims and theinvention.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent, is:

1. A bearing structure for a rotary shaft comprising a pair of radialbearings disposed adjacent the. opposite ends of the shaft, and athrustbearing intermediate said radial bearings. each of said bearingscomprising a plurality of pivotally mounted bearing shoes, the shoes ofthe radial bearing being symmetrically disposed with respect to a centerline drawn through the center of the shaft and one of the shoes beingpositioned directly below the shaft, said one shoe being adjustablymounted, a collar on the shaft, a plurality of thrust bearing shoes incontact with opposite sides of the collar and positioned symmetricallywith respect to' a vertical line drawn through the center of the shaftbut all disposed considerably above the lower portion of the collar allof said thrust bearing shoes being adjustably. mounted, and means forlubricating the radial and thrust bearing shoes.

2. A bearing structure for a rotary shaft comprising a pair of radialbearings'disposed adjacent the opposite ends of the shaft, and a thrustbearing intermediate said radial bearings, each of said bearingscomprising a plurality of pivotaily mounted bearing shoes, the shoes ofthe radial bearing being disposed symmetrically with respect to avertical line drawn through the center of the shaft and one of the shoesbeing positioned directly below the shaft, said one shoe beingadjustably mounted, a collar on the shaft; a plurality of thrust bearingshoes in contact with opposite sides of the collar and positionedsymmetrically with respect to a vertical line drawn through the centerof the shaft but all disposed considerably above the lower portion ofthe collar all of said thrust bearing shoes being adiustably mounted,and means for lubricating the radial and thrust bearing shoes, saidmeans comprising aperturedpipes in the region of the leading edges ofthe radial bearing shoes, said pipes being closed at one end andsupplied at the other end with oil under pressure, a chamber in whichthe oil collects positioned directly below the thrust collar, the lowersurfaces of said collar being adapted to move through the collectedlubricant as the shaft rotates in order to wet the thrust bearing.

, 3. A bearing structure for-a rotary shaft comsymmetrically withrespect to a ver ical line drawn through the center of the shaft but alldisposed considerably above the lower portion of the collar all of saidthrust bearing shoes being adjustably mounted, means for lubricating theradial and thrust bearing shoes, and means including set screws forlocking said shoes in their adjusted positions.

WILLIAM G. BALDENHOFER.

